A research institute of the OVPR
 
Geothermal Resources
  
The Indiana Shallow Geothermal Monitoring Network: A test bed for facilitating the optimization of geothermal heat pumps in the glaciated Midwest

Map of Indiana showing the locations of Geothermal Monitoring Network sites and the diversity of surficial geologic deposits.
Click here to zoom to each site location.

Shallow geothermal energy represents a renewable resource that can be further developed via ground-source heat pumps (GSHPs). The costs of these systems can be minimized by allowing designers and installers to make decisions about construction technologies that take into account the appropriate thermal properties and predominant moisture regime of the geologic material being utilized.

Researchers at the Center for Geospatial Data Analysis and Indiana Geological Survey developed a comprehensive monitoring network that provides in-situ measurements of shallow subsurface thermal conductivity, temperature gradients, and soil moisture. Continuous measurements of 1) thermal gradients in the upper 6 feet of the ground, 2) thermal conductivity, and 3) volumetric moisture content are collected at six monitoring sites near Indianapolis and Fort Wayne, the two largest population centers in Indiana

Although software allows GSHP installers to calculate optimal lengths and configurations of ground-coupling geothermal systems, there are input parameters that must first be determined for these applications, including soil thermal properties and earth temperatures. The fundamental control on heat transfer for a ground-coupled heat pump system is the thermal conductivity of the earth materials in which the system is installed. The determination of thermal properties for typical unconsolidated sediments in the upper 6 feet of the ground will support the design of more efficient systems by allowing GSHP installers to efficiently tailor the configurations of their systems to specific geological conditions and also to account for seasonal changes.

Site locations and data

Site name (click name for data)

Site #

Geologic setting

Texture at 4-foot depth

Bulk density (g/cm3)

Flat Rock River

1

alluvial terrace

sandy clay loam

1.11-1.32

Bradford Woods

2

alluvial terrace

silt loam

1.32-1.58

Shelbyville Moraine

3

moraine crest

silty clay loam

1.41-1.79

Eel River Valley

4

outwash terrace

sandy loam

1.46-1.71

Wabash Moraine

5

moraine crest

clay loam

1.64-1.80

Ball State Univ.

6

till plain

silt loam

NA

For more information contact Shawn Naylor (snaylor@indiana.edu).



 
 
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